Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) - Manual (Page 61)

Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013 51
Installation Chapter 2
Control Cables
Control cable entry/exit should be located near the terminal blocks; customer’s
connections are to be routed along the empty side of the terminals. Nylon cable
tie loops are provided at the left, front corner of the cabinet to route control
cables safely behind the low voltage panel hinges. Cables should be routed so they
do not interfere with the swing of the low-voltage panels.
Fiber-Optic Cables
The small, gray, fiber-optic cables are fragile and must be protected during
installation from sharp bends and impact.
Power Factor Correction Capacitors
The controller can be installed on a system with power factor correction
capacitors. The capacitors must be located on the line side of the controller. This
is required to prevent damage to the SCRs in the MV SMC Flex controller. A
separate switching contactor is recommended to apply the capacitors only after
the bypass contactor has closed, and to remove them when the bypass contactor
opens. See
Figure 34 for two different acceptable connection methods.
When discharged, a capacitor has essentially zero impedance. For switching,
sufficient impedance should be connected in series with the capacitor bank to
limit the inrush current. A method of limiting the surge current is to add
inductance in the capacitor conductors. This can be accomplished by putting
turns or coils of wire in the power connections to the capacitors (6-inch diameter
coil, six loops). For more information, refer to NEMA standard ICS 2, Part 2,
Capacitor Applications.
Care should be used in mounting the coils so that they are not stacked directly on
top of each other or they will have a cancelling effect. Also, the coils should be
mounted on insulated supports away from metal parts so they will not act like
induction heaters.
TIP Consult the factory if there are any capacitors on the same branch circuit as the
MV SMC Flex.
ATTENTION: Any covers or barriers removed during installation must be
replaced and securely fastened before energizing equipment. Failure to do so
may result in severe burns, injury or death.